Ok ill first start by giving my plans for my 2007 shelby gt500.
1. I want to go with off road xpipe and either bassanni or borla atak mufflers.
2. I want to lower my car
My question is What all will i need to install the exhaust? O2 extensions? What kind of tuner? And as far as lowering it, is it as easy as changing out springs, or is there more involved as far as parts? Any help would be appreciated, thanks! And Merry Christmas

 

I had a friend install my lowering springs. No other parts required. I do intend to get the alignment checked next spring before I drive it much.
Not sure on the x-pipe. IF it deletes O2 sensors you'd need a tune that turns them off.